The present invention relates to electrosurgical instruments and systems for treating a surgical site on a human or animal body such as biological tissue by the application of energy. More particularly, the invention relates to surgical devices and methods for applying high frequency energy to modify the characteristics of the tissue such as by ablation in combination with aspiration of any by-products from a surgical site.
Numerous surgical instruments for the treatment of biological tissue through the application of energy in a wide variety of medical procedures are known in the art. For example, U.S. Pat. No. 4,593,691 to Lindstrom et al., U.S. Pat. No. 4,033,351 to Hetzel, and U.S. Pat. No. 5,403,311 to Abele et al. are examples of electrosurgical probes for use during an electrosurgical procedure such as for cutting or ablating tissue. U.S. Pat. No. 5,458,596 to Lax et al. shows an example of an electrosurgical probe for the contraction of tissue by delivering electrical energy to the treatment tissue. Also, U.S. Pat. No. 3,828,780 to Morrison and U.S. Pat. No. 5,277,696 to Hagen show electrosurgical instruments which deliver electrical energy for coagulation during surgical procedures.
The use of these instruments typically involves the transmission of energy to a distal end of the electrosurgical probe or instrument. The distal end is inserted into the body to a surgical site of a patient to apply energy during the procedure. The frequency, power, and voltage generated by the electrical instrument and transmitted to the distal end are selected depending on the type of procedure for which the instrument is being used. For instance, such instruments are used for a variety of procedures such as heating, softening, shrinking, cutting and ablating tissue.
Because such instruments may be used for different procedures, the tissue (or other body part) being treated may respond differently depending on the treatment being performed. For instance, if the instrument is used to ablate the tissue, smoke and charring may be generated during the procedure or residual tissue debris may remain after treatment. Unwanted air bubbles or excess fluid may also be present in the treatment area that may interfere with effective treatment of the tissue and should be removed from the surgical site during the procedure. Thus, it is desirable to provide an electrosurgical device for aspirating the region being treated to remove smoke, tissue debris, excess fluid and other unwanted matter from the tissue site being treated.
During the usage of prior instruments, however, such as in numerous of the above-mentioned instruments, the removal of unwanted matter generally requires the separate provision of an aspiration device. The use of two separate instruments increases the treatment time because the suction instrument must be separately inserted into the surgical site, used, and removed from the site before and/or after the electrosurgical treatment instrument is inserted or used at the site. Additionally, a separate suction instrument may be inserted into the surgical site through another access point which creates another portal in the patient""s body which possibly creates further complications such as infection and scarring.
U.S. Pat. No. 5,520,685 to Wojciechowicz, U.S. Pat. No. 4,682,596 to Bales and U.S. Pat. No. 4,347,842 to Beale disclose suction devices in various combinations and configurations with the electrosurgical probe. U.S. Pat. No. 5,195,959 to Smith also discloses an electrosurgical device with suction and irrigation to supply electrically conductive fluid which adds even more material to the surgical site and would need to be removed during the procedure. Wojciechowicz, in particular discloses a suction coagulator with a suction lumen for the suction of by-products of electrosurgery through the instrument through a tip. Further, Hagen discloses a suction device for aspirating fluid through the surgical probe.
However, the arrangement of the suction lumen in relationship to the electrosurgical portion is such that blockage or clogging of the suction lumen can occur which could complicate the surgical procedure and unwanted or unnecessary ablation could occur. Charred and ablated tissue and coagulated blood often clog the tips of electrosurgical devices.
Therefore, it would be desirable to provide an instrument that may be used not only to treat a patient but also to aspirate the treatment area during treatment to simultaneously remove unwanted material. The surgical device and method should be simple and operate in a standard surgical environment. The electrosurgical instrument should provide the surgeon the ability to ablate, cut or coagulate in the same device while providing a suction means to aspirate surgical by-products from the surgical site. The suction and aspiration should be anti-clogging such that the device does not cause unwanted nor undesirable effects due to blockage. Such instrument and method should be able to precisely treat biological tissue with energy while efficiently allowing the surgeon to perform the medical procedure quickly without the need to utilize multiple instruments for the treatment.
It is, therefore, an object of the present invention to provide a surgical instrument and method for the application of energy to a treatment area of a patient and for the aspiration of unwanted matter, such as smoke, air bubbles and biological waste debris from the surgical site.
It is a related object of the present invention to provide a combination of electrosurgical and aspiration instrument that provides an energy application surface area that applies energy uniformly over the treatment area and also permits aspiration therethrough so as to limit clogging.
It is another object of the present invention to provide a combination electrosurgical and aspiration instrument having both an active electrode and a return electrode at a distal tip of the instrument such that energy distribution is substantially limited to the distal tip surface.
These and other objects and features are accomplished in accordance with the principles of the present invention by providing a probe having a cannula with at least one electrode for the transmission and application of energy to a treatment site along an energy application surface as well as a suction lumen through which unwanted matter and surgical by-products may be aspirated from the treatment area. Preferably, at least one electrode, an active electrode is provided on a distal end of the probe. A return or indifferent electrode may located on the patients"" body or on the probe. The instrument is coupled to an energy generator that preferable includes controls that may be used to regulate the power, frequency, and voltage applied to the instrument to vary the type of treatment for which the instrument is used. The regulation may include feedback controls.
In one embodiment of the invention, the active electrode is provided with a plurality of small passages therethrough in a fluid communication with the suction lumen of the instrument. An active electrode with such aspiration passages may be in the form of a mesh, a disc having perforations therethrough, or plural conductors supported by an insulator with apertures therethrough. Thus, aspiration of the treatment area occurs through at least a portion of the energy application surface. If desired, both the active and return electrodes may be positioned in substantially the same plane such that energy distribution is substantially restricted to a substantially planar surface area, such as the surface area of the distal tip.
In an alternative embodiment of the present invention, the surgical instrument has a shaft having distal and proximal ends. The shaft also defines at least one lumen. The lumen has at least one aspiration opening at the distal end. An active electrode is located at the distal end of the shaft which defines an energy application surface. The active electrode is electrically coupled to a power source. A return electrode is coupled to the power supply such that a current path from the active electrode to the return electrode passes over the aspiration opening to prevent clogging of the opening. The return electrode may be located on a portion of the body of a patient or on the shaft.
As negative pressure is applied to the lumen, matter that is in the surgical site is aspirated through the aspiration opening. The opening is configured to prevent clogging of the aspirated matter at the distal end. The aspiration opening may be defined by the active electrode which is configured to prevent clogging of the aspiration opening and allow continued desiccation of the unwanted aspirated matter such that the matter will move easily through the aspiration lumen.
These and other features and advantages of the present invention will be readily apparent from the following drawings and detailed description of the invention, the scope of the invention being set out in the appended claims.